62 SEEDING AND PLANTING 



place the original mixed stands with single species, when the 

 regeneration is attained by direct seeding or planting. This is 

 particularly true of white pine, red pine, western yellow pine, 

 Engelmann spruce, and Douglas fir in the United States, and 

 Scotch pine and Norway spruce in Europe. The ease with which 

 pure stands can be artificially established, their uniform and rapid 

 juvenile growth, and their early promise of yielding large finan- 

 cial returns on the investment are important reasons for their 

 formation. One of the reasons why pure artificial stands are the 

 rule rather than the exception is that mixed crops make higher 

 demands on the forester, as it is much more difficult and trouble- 

 some to give proper attention and care to each of several species 

 in a mixed crop than to look after one species only. 1 



In recent years, following the leadership of Gayer, there has 

 been a strong reaction in Europe against establishing pure forests 

 by seeding and planting. Even such tolerant conifers as spruce 

 are grown more and more with from 10 to 15 per cent of hard- 

 woods. 2 



The present practice of wide spacing in the United States, the 

 non-filling of blanks, and seeding and planting on unprepared sites 

 naturally result in a large amount of volunteer growth in the re- 

 generation. When not overabundant and of acceptable species, 

 this growth should be encouraged as it may correct the disadvan- 

 tages of a pure crop. 



2. PURE CROPS IN ARTIFICIAL REPRODUCTION 



In general, species that are dense-foliaged and that form and preserve 

 a complete leaf canopy to an advanced age may be grown in pure stand 

 because the density of the canopy is the chief factor in preserving the qual- 

 ity of the site. Beech, maple, spruce, fir, and similar dense-foliaged 

 species are the best to grow in pure stands because of their shad- 

 ing effect on the forest floor. Oak, chestnut, and pine, although 

 much less tolerant, are often grown in pure stand because of their 

 high commercial value. Attempts should not be made to bring 

 artificial stands of ash, cherry, walnut, tulip, and other dependent 

 trees to maturity in pure stands. 



1 Gayer, Karl: Der Waldbau. 4. Aufl., S. 223. Berlin, 1898. 



2 Ibid.: Der gemischte Wald. S. 9. Berlin, 1886. 



